JP2012247177A - Heating furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating furnace which maintains the temperature distribution in a furnace space more uniform and has high energy efficiency.SOLUTION: The heating furnace 1 includes a furnace space 30 for heating a substance 100 to be heated, an inner wall surface 40 having a first inner wall surface 41 and a second inner wall surface 42 opposite to each other holding the substance 100 to be heated in the furnace space 30 and forming the furnace space 30, and a heating device 20 arranged on the first inner wall surface 41 and the second inner wall surface 42 for heating the substance 100 to be heated with a heating surface 21. The first inner wall surface 41 has a first incline 41a on the upstream side in the transportation direction T of the substance 100 to be heated and a second inclined part 41b on the downstream side in the transportation direction T, while the second inner wall surface 42 has a third inclined part 42a on the upstream side in the transportation direction T and a fourth inclined part 42b on the downstream side in the transportation direction T, so that the heating surface 21 of the heating device 20 is disposed in an inclined manner toward the center side of the furnace space 30.

Description

  The present invention relates to a heating furnace for heating various articles, and more particularly to a heating furnace used for baking foods such as rice crackers and baked goods.

  Conventionally, in the production of foods such as rice crackers and baked confectionery, a baking process for heating and baking the dough has been required, and various types of heating furnaces are used in this baking process. Such a heating furnace includes a batch type and a continuous type. In order to improve productivity, it is desirable to use a continuous heating furnace.

  For this reason, in a general production line such as baked confectionery, the inside of a tunnel-shaped heating furnace partitioned into a plurality of regions according to heating conditions is heated and baked while conveying an object to be heated by a chain conveyor or the like. Many heating furnaces configured to perform the above are used (see, for example, Patent Document 1).

JP 2005-295930 A

  In baking food, it is important to keep the temperature distribution in the furnace space uniform and to heat the object to be heated uniformly. When unevenness occurs in the heating, not only the flavor and texture of the final product are changed, but also the appearance is impaired due to the occurrence of burnt eyes, deformation, etc., which contributes to quality deterioration.

  For this reason, for example, in the invention described in Patent Document 1, a plurality of temperature sensors are arranged in the furnace, the amount of fuel and air supplied to the burner and the like is controlled based on the measurement results of these temperature sensors, and the furnace The temperature inside is kept constant.

  However, in the invention described in Patent Document 1, the shape of the furnace space for making the temperature distribution uniform and the direction of supply of heat from the heating means are not taken into consideration. There was a problem that it was likely to occur. For this reason, in order to keep the temperature distribution in the furnace space uniform, combustion control of a burner or the like must be frequently performed, resulting in a problem that energy efficiency deteriorates and running cost increases.

  In view of such circumstances, the present invention is intended to provide a heating furnace with high energy efficiency while keeping the temperature distribution in the furnace space more uniform.

  (1) The present invention includes a furnace space for heating an object to be heated, a first inner wall surface and a second inner wall surface facing each other across the object to be heated in the furnace space, An inner wall surface that forms an inner space; and a heating device that is disposed on the first inner wall surface and the second inner wall surface and that heats the object to be heated by a heat generating surface that generates heat. The inner wall surface has a first inclined portion on the upstream side in the conveying direction of the heated object and a second inclined portion on the downstream side in the conveying direction, and the second inner wall surface is in the conveying direction. And a fourth inclined portion on the downstream side in the transport direction, and the first inclined portion and the second inclined portion are formed on the first inner wall surface. Formed so as to gradually approach the second inner wall surface as the distance from the center along the transport direction increases. The inclined portion and the fourth inclined portion are formed so as to gradually approach the first inner wall surface as they move away from the center of the second inner wall surface along the transport direction, and the heating device includes the first Upstream and downstream in the transport direction from the center of the first inner wall surface in the inner wall surface, and upstream and downstream in the transport direction from the center of the second inner wall surface in the second inner wall surface. It is a heating furnace characterized by being arrange | positioned so that the said heat generating surface may face the center side of the said in-furnace space while being arrange | positioned at the side.

  (2) In the heating apparatus according to the second aspect of the invention, the first inner wall surface may be configured such that the first inner wall surface is closer to the first inner wall surface than the upstream end and the downstream end in the transport direction of the first inner wall surface. The second inner wall surface is closer to the center of the second inner wall surface than the upstream and downstream ends of the second inner wall surface in the transport direction. The heating furnace according to (1) above, wherein the heating furnace is arranged as described above.

  (3) The present invention is also provided on the upstream side in the transport direction, and is provided on the downstream side in the transport direction, and a carry-in entrance that is an opening for transporting the object to be heated into the furnace space. The heating furnace according to (1) or (2), further including a carry-out port that is an opening for carrying out an object from the furnace space.

  (4) The present invention is also the heating furnace according to any one of (1) to (3) above, wherein an inclination angle of the heating surface with respect to the transport direction is 10 to 30 °. .

  According to the heating furnace according to the present invention, the temperature distribution in the furnace space can be kept more uniform and the energy efficiency can be improved.

It is the schematic sectional drawing which looked at the heating furnace concerning the embodiment of the present invention from the front. It is the schematic sectional drawing which looked at the heating furnace from the right side. (A) And (b) It is the schematic which showed the shape of the space in a furnace, and arrangement | positioning of a heat generating surface. (A)-(d) It is the figure which showed an example of the simulation which the inventor of this application performed. (A) And (b) It is the schematic which showed the example of the other cross-sectional shape in xy plane of the space in a furnace. (A) And (b) It is the schematic which showed the example of the other cross-sectional shape in xy plane of the space in a furnace. (A) And (b) It is the schematic which showed the example of the other cross-sectional shape in yz plane of the space in a furnace. (C) It is the schematic which showed the example which inclined the heat generating surface also with respect to the z direction. (A)-(c) It is the schematic which showed the example of the usage condition of a heating furnace. (A) And (b) It is the schematic which showed the conventional heating furnace of the comparative example. (A) And (b) It is the schematic which showed the heating furnace of the Example of this invention. It is the table | surface which showed the result of the heating test.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the heating furnace 1 according to the present embodiment will be described. FIG. 1 is a schematic cross-sectional view of the heating furnace 1 according to the present embodiment as viewed from the front, and FIG. 2 is a schematic cross-sectional view of the heating furnace 1 as viewed from the right side. In the following description, the horizontal direction when the heating furnace 1 is viewed from the front is the x direction, the vertical direction is the y direction, and the front and rear horizontal direction is the z direction. Accordingly, FIG. 1 is a cross-sectional view of the heating furnace 1 in the xy plane, and FIG. 2 is a cross-sectional view of the heating furnace 1 in the yz plane.

  As shown in these drawings, the heating furnace 1 includes an upper furnace wall 10, a lower furnace wall 11, a left furnace wall 12, a right furnace wall 13, a front furnace wall 14, and a rear furnace wall 15 ( Hereinafter, they may be collectively referred to as furnace walls 10 to 15) and a heating device 20. Further, the left furnace wall 12 is provided with a carry-in port 12a which is a horizontally long and substantially rectangular opening, and the right furnace wall 13 has a carry-out port 13a which is substantially the same shape as the carry-in port 12a. It is provided at a position facing 12a.

  The heating furnace 1 of the present embodiment is a continuous heating furnace that heats a plurality of objects to be heated 100 while transporting the interior of the furnace space 30 by the transport device 110. That is, the object to be heated 100 is carried into the furnace space 30 through the carry-in port 12a by the transfer device 110, heated by the heating device 20 for a predetermined time while moving in the furnace space 30, and then through the carry-out port 13a. It is to be carried outside. Therefore, in this embodiment, the conveyance direction T of the article to be heated 100 is a direction (x positive direction) that goes horizontally from the carry-in port 12a to the carry-out port 13a.

  Each of the furnace walls 10 to 15 has a structure in which a firestone is arranged inside an outer shell composed of an angle and a plate, and the firestone does not fall off by arranging a presser wire net further inside the firestone. It is configured. Among the furnace walls 10 to 15, the left furnace wall 12, the right furnace wall 13, the front furnace wall 14, and the rear furnace wall 15 are substantially flat walls erected in the vertical direction, and the upper furnace wall 10 and The lower furnace wall 11 has a substantially V-shaped (open U-shaped) wall in a front view extending in the front-rear horizontal direction.

  Two heating devices 20 are arranged on the upper furnace wall 10 and the lower furnace wall 11 so as to be fitted inside the openings, respectively. Further, external covers 10 a and 11 a are appropriately provided outside the upper furnace wall 10 and the lower furnace wall 11. A heat insulating material is disposed between the outer cover 10a and the upper furnace wall 10 and between the outer cover 11a and the lower furnace wall 11 as necessary.

  A furnace space 30 that is a space for heating the article to be heated 100 is formed by an inner wall surface 40 that combines the inner surfaces of the furnace walls 10 to 15. In the present embodiment, the left and right side portions viewed from the front of the first inner wall surface 41 constituted by the upper furnace wall 10 of the inner wall surface 40 are inclined in a substantially C shape, and the lower furnace wall 11 The left and right side portions viewed from the front of the configured second inner wall surface 42 are inclined in a substantially inverted C shape.

  Specifically, a first inclined portion 41 a that is lowered on the upstream side is provided on the upstream side in the transport direction T on the first inner wall surface 41, and the downstream side is on the downstream side in the transport direction T on the first inner wall surface 41. A lowered second inclined portion 41b is provided. In addition, a third inclined portion 42a whose upstream side is raised is provided on the upstream side in the transport direction T on the second inner wall surface 42, and the downstream side is raised on the downstream side in the transport direction T on the second inner wall surface 42. Four inclined portions 42b are provided. Although details will be described later, by inclining the first inner wall surface 41 and the second inner wall surface 42 opposed to each other with the object to be heated 100 in the furnace space 30 interposed therebetween, the temperature of the furnace space 30 is increased. It is possible to make the distribution more uniform and to increase the energy efficiency (thermal efficiency).

  The heating device 20 is configured to include a heat generating surface 21 that generates heat for heating the article to be heated 100, and is configured from an infrared burner in the present embodiment. Specifically, the heating device 20 includes a plurality of substantially rectangular ceramic plates having a large number of fine holes arranged along the longitudinal direction, and a mixture of fuel gas and air is burned on the surface of the ceramic plates. It is configured. Therefore, in the present embodiment, the heat generating surface 21 is the surface of the ceramic plate, and the object to be heated 100 is heated by the heat generated by the heat generating surface 21 (mainly infrared radiation). The fuel gas and air are supplied from supply sources not shown.

  The heating device 20 is disposed on each of the first inclined portion 41a and the second inclined portion 41b of the first inner wall surface 41, and the third inclined portion 42a and the fourth inclined portion 42b of the second inner wall surface. ing. That is, the heating furnace 1 of the present embodiment includes four heating devices 20 and is configured to heat the article to be heated 100 from both above and below.

  In addition, in this embodiment, since the dimension of the front-back direction (z direction) of the heating furnace 1 is comprised comparatively long, as shown in FIG. 2, the length 2 of the heat generating surface 21 (ceramics plate) is equal. One heating device 20 is configured by arranging the two burners 20a and 20b in series at a predetermined interval. As described above, by disposing the two burners 20a and 20b at a predetermined interval, it is possible to prevent the central portion of the furnace space 30 from being excessively heated. That is, the temperature distribution in the furnace space 30 can be made more uniform. The length of the two burners 20a and 20b and the size of the distance between them are not particularly limited, and may be set appropriately according to the size of the furnace space, the performance of the burners 20a and 20b, and the like. Good.

  The four heating devices 20 are arranged so as to be inclined in the xy plane so that the heat generating surface 21 faces the center side of the in-furnace space 30 with the longitudinal direction parallel to the z direction. The two heating devices 20 arranged on the first inner wall surface 41 are arranged near the center side of the first inner wall 41 in the x direction and are arranged on the second inner wall surface 42. 20 are arranged near the center side of the second inner wall 42 in the x direction. Although details will be described later, by arranging the heating device 20 in this way, it is possible to make the temperature distribution in the furnace space 30 more uniform and to improve the energy efficiency.

  In addition, although illustration is abbreviate | omitted, the conveying apparatus 110 of this embodiment conveys the several to-be-heated material 100 continuously by making the metal-mesh-like endless belt which mounted the to-be-heated material 100 drive | run by a sprocket. It is a belt conveyor system. However, the present embodiment is not limited to this, and the transfer device 110 may be of another type such as a chain conveyor or a walking beam.

  Next, details of the shape of the furnace space 30 and the arrangement of the heat generating surface 21 will be described. FIGS. 3A and 3B are schematic views showing the shape of the furnace space 30 and the arrangement of the heat generating surface 21. 1A is a schematic cross-sectional view of the furnace space 30 viewed from the front, and FIG. 1B is a schematic cross-sectional view of the furnace space 30 viewed from the right side. As shown in FIG. 6A, the cross-sectional shape of the furnace space 30 in the xy plane is substantially octagonal, and as shown in FIG. 5B, the yz plane of the furnace space 30 is formed. The cross-sectional shape in is substantially rectangular. That is, the furnace space 30 is configured in a substantially octagonal prism shape.

  A first inner wall surface 41 that is a ceiling portion of the inner wall surface 40 that forms the furnace inner space 30 has a first inclined portion 41a on the negative side in the x direction (that is, on the upstream side in the transport direction T), and is positive in the x direction. It has the 2nd inclined part 41b on the side (namely, the downstream of the conveyance direction T). The first inclined portion 41a is formed so as to be inclined by an angle θ1 parallel to the z direction and with respect to the x direction. It is configured to approach the inner wall surface 42. The second inclined portion 41b is formed so as to be inclined by an angle θ2 parallel to the z direction and with respect to the x direction, and gradually increases from the center O1 of the first inner wall surface 41 in the x positive direction. It is comprised so that the 2 inner wall surface 42 may be approached.

  Similarly, the second inner wall surface 42 which is the bottom portion of the inner wall surface 40 forming the furnace space 30 has a third inclined portion 42a on the x direction negative side (that is, on the upstream side in the transport direction T), A fourth inclined portion 42b is provided on the positive side in the x direction (that is, on the downstream side in the transport direction T). The third inclined portion 42a is formed so as to be inclined by an angle θ3 parallel to the z direction and with respect to the x direction, and gradually increases as the distance from the center O2 of the second inner wall surface 42 in the negative x direction increases. It is configured to approach the inner wall surface 41. The fourth inclined portion 42b is formed so as to be inclined by an angle θ4 parallel to the z direction and with respect to the x direction, and gradually increases from the center O2 of the second inner wall surface 42 in the x positive direction. 1 is configured to approach one inner wall surface 41.

  According to various simulations and experiments conducted by the inventors of the present application, the first to fourth inclined portions 41a, 41b, 42a, 42b are provided on the first inner wall surface 41 and the second inner wall surface 42 in this way. As a result, the air in the furnace space 30 can be appropriately convected and circulated, so that the temperature distribution in the furnace space 30 can be made more uniform and the energy efficiency (thermal efficiency) can be improved than before. In order to make the temperature distribution in the furnace space 30 more uniform and increase energy efficiency, the shape of the furnace space 30 is preferably symmetrical with respect to the center O of the furnace space 30. .

  For this reason, in this embodiment, while forming the 1st inclination part 41a and the 2nd inclination part 41b mutually symmetrically, the 3rd inclination part 42a and the 2nd inclination part 42b are mutually formed symmetrically. . Further, the first inner wall surface 41 and the second inner wall surface 42 are formed symmetrically with each other. That is, the inclination angles θ1 to θ4 are all the same angle.

  Here, the values of θ1 to θ4 are not particularly limited, but according to various simulations and experiments performed by the inventors of the present application, in order to further improve the temperature distribution and energy efficiency of the in-furnace space 30. Is preferably in the range of 10 to 30 °. In this embodiment, θ1 to θ4 are all 20 °.

  Further, according to various simulations and experiments performed by the inventors of the present application, the ratio of the y-direction dimension Ly and the x-direction dimension Lx of the furnace space 30 further improves the temperature distribution and energy efficiency of the furnace space 30. Therefore, it is preferable that Ly: Lx = 1: 1.2 to 1.5.

  The heat generating surface 21 is formed in an elongated and substantially rectangular shape, and is arranged so that the longitudinal direction is parallel to the z direction. The heat generating surface 21 is outside the center O1 of the first inner wall surface 41 in the first inner wall surface 41, that is, the positive side in the x direction and the negative side in the x direction with respect to the center O1 of the first inner wall surface 41. Respectively. Further, the heat generating surface 21 is outside the center O2 of the second inner wall surface 42 in the second inner wall surface 42, that is, the positive side in the x direction and the negative side in the x direction with respect to the center O2 of the second inner wall surface 42. Respectively.

  And in the 1st inner wall surface 41, each heat-emitting surface 21 is the center of the 1st inner wall surface 41 rather than the x direction negative side edge part 41c and the x direction positive side edge part 41d of the 1st inner wall surface 41 in the x direction. The heat generating surface 21 is arranged at a position close to O1, and each heat generating surface 21 in the second inner wall surface 42 is more in the x direction than the x direction negative side end portion 42c and the x direction positive side end portion 42d of the second inner wall surface 42. The second inner wall surface 42 is disposed at a position close to the center O2.

  According to various simulations and experiments performed by the inventor of the present application, in order to make the temperature distribution in the furnace space 30 more uniform and increase the energy efficiency, the arrangement of the heating surface 21 is the shape of the furnace space 30. Similarly, it is preferable to be symmetric with respect to the center O of the furnace space 30. For this reason, in this embodiment, the heat generating surface 21 is arranged symmetrically with respect to the center O of the in-furnace space.

  Each heat generating surface 21 is arranged in a state where the width direction is inclined at the same angle with respect to the x direction so as to face the center O side of the furnace space. Specifically, each heat generating surface 21 is inclined in the width direction by an angle θ5 with respect to the x direction in the xy plane, in other words, as shown in FIG. 3A, the normal direction of the heat generating surface 21 Are arranged at an angle of θ5 with respect to the y direction.

  Here, the inclination angle θ5 of the heat generating surface 21 is not particularly limited, but according to various simulations and experiments performed by the inventors of the present application, the temperature distribution in the furnace space 30 is made more uniform. In order to increase energy efficiency, the value of the inclination angle θ5 is preferably in the range of 10 to 30 °, and more preferably in the range of 15 to 25 °. For this reason, in this embodiment, the inclination angle θ5 of the heat generating surface 21 is set to 20 ° equal to θ1 to θ4. Therefore, each heat generating surface 21 is parallel to the first to fourth inclined portions 41a, 41b, 42a, 42b on which the heat generating surfaces 21 are arranged.

  4A to 4D are diagrams showing an example of a simulation performed by the inventor of the present application. In this simulation, the cross-sectional shape of the furnace space 30 in the xy plane is set to a hexagonal shape, and the inclination angles θ1 to θ4 of the first to fourth inclined portions 41a, 41b, 42a, and 42b are set to 10 °. ing. Then, the inflow of outside air from the carry-in port 12a and the outflow of furnace air from the carry-out port 13a accompanying the conveyance of the object to be heated 100 are set, and the inclination angle θ5 and the arrangement of the heating surfaces 21 of the four heating devices 20 are set The temperature distribution in the furnace space 30 when changed was calculated by the finite element method.

  As described above, by providing the first to fourth inclined portions 41a, 41b, 42a, and 42b, the air in the furnace space 30 can be appropriately convectively circulated. In any of the examples (a) to (d), it can be kept uniform to some extent. However, due to the influence of the inflow of outside air from the carry-in port 12a and the outflow of furnace air from the carry-out port 13a, a temperature gradient is generated in the vicinity of the carry-in port 12a in any of the examples shown in FIGS. ing.

  The inventor of the present application has found that the range in which this temperature gradient occurs can be reduced by devising the inclination angle θ5 and the arrangement of the heat generating surface 21. Specifically, in the example shown in FIG. 1A, the inclination angle θ5 of the heat generating surface 21 is set to 5 °, and in this case, it reaches the center O of the furnace space 30 relatively. There is a temperature gradient over a wide range.

  Next, in the example shown in FIG. 5B, the inclination angle θ5 of the heat generating surface 21 is set to 10 °, that is, the heat generating surface 21 is parallel to the first to fourth inclined portions 41a, 41b, 42a, 42b. It is trying to become. In this example, the range in which the temperature gradient occurs is smaller than in the example shown in FIG. In the example shown in FIG. 10C, the inclination angle θ5 of the heat generating surface 21 is set to 20 °, and in this case, a range in which a temperature gradient further occurs than in the example shown in FIG. Has been reduced.

  In the example shown in FIG. 4D, the inclination angle θ5 of the heat generating surface 21 is set to 10 °, and each heat generating surface 21 is separated in the x direction from the example shown in FIG. Arranged. In this case, the range in which the temperature gradient is generated extends in the x direction, and the temperature gradient is generated over a wider range than the example shown in FIGS.

  The inventor of the present application repeats the experiment by the actual machine based on the simulation result together with the simulation by such a computer, so that (1) the furnace 21 together with the first to fourth inclined portions 41a, 41b, 42a, 42b Inclining toward the center O side of the inner space 30, (2) The inclination angle θ5 of the heat generating surface 21 is within a range of 10 to 30 °, more preferably 15 to 25 °, and (3) each heat generating surface. 21 is arranged close to each other in the x direction (conveying direction T) toward the center O side of the furnace space 30, and (4) the heating surface 21 is arranged symmetrically with respect to the center O of the furnace space 30. It is effective to make the temperature distribution in the furnace space 30 uniform and increase the energy efficiency when there is an inflow and outflow of air from the carry-in port 12a and the carry-out port 13a. It was found that there.

  In the present embodiment, based on such new knowledge that has not been considered in the past, the shape of the furnace space 30 and the arrangement of the heating surfaces 21 in the heating furnace 1 are set to the shape and arrangement described in FIG. ing. Further, in the present embodiment, the heating device 20 is disposed so as to be embedded in the upper furnace wall 10 and the lower furnace wall 11, so that the space between the heating device 20 and the first inner wall surface 41 and the second inner wall surface 42 is increased. The hot air is prevented from staying in the air and the energy efficiency is further increased.

  Further, the heat generating surfaces 21 are arranged on the first to fourth inclined portions 41a, 41b, 42a, 42b, and the inclination angle θ5 of the heat generating surface 21 and the first to fourth inclined portions 41a, 41b, 42a, 42b are arranged. By aligning the inclination angles θ1 to θ4, smoother convection circulation is realized.

  Next, other forms of the furnace space 30 and the heat generating surface 21 will be described. FIGS. 5A and 5B, and FIGS. 6A and 6B are schematic views illustrating examples of other cross-sectional shapes in the xy plane of the furnace internal space 30. In the above-described example, an example in which the cross-sectional shape of the furnace space 30 in the xy plane is a substantially octagonal shape is shown, but the cross-sectional shape of the furnace space 30 in the xy plane is not limited to this. Any shape may be used as long as it has the fourth inclined portions 41a, 41b, 42a, and 42b.

  For example, as shown in FIG. 5A, the cross-sectional shape in the xy plane of the furnace space 30 may be a substantially hexagonal shape. Further, as shown in FIG. 5 (b), the first to fourth inclined portions 41a, 41b, 42a, 42b are respectively configured from regions having two different inclination angles, whereby the xy plane of the in-furnace space 30 is obtained. The cross-sectional shape in FIG.

  Specifically, in the example shown in FIG. 5B, the first inclined portion 41a is composed of a first region 41a1 and a second region 41a2 having different inclination angles, and the second inclined portion. 41b is composed of a first region 41b1 and a second region 41b2 having different inclination angles. The third inclined portion 42a includes a first region 42a1 and a second region 42a2 having different inclination angles, and the fourth inclined portion 42b includes the first region 42b1 and the first region 42b1 having different inclination angles. 2 regions 42b2.

  In FIG. 5B, the inclination angle of the outer second regions 41a2, 41b2, 42a2, and 42b2 is determined from the inclination angle of the first regions 41a1, 41b1, 42a1, and 42b1 on the inner side (center O1, O2 side). However, the inclination angles of the inner first regions 41a1, 41b1, 42a1, and 42b1 may be made larger than the inclination angles of the outer second regions 41a2, 41b2, 42a2, and 42b2. Needless to say, the first to fourth inclined portions 41a, 41b, 42a, and 42b may be configured from three or more regions having different inclination angles.

  In addition, the positions and ranges in which the first to fourth inclined portions 41a, 41b, 42a, and 42b are provided on the first inner wall surface 41 and the second inner wall surface 42 are not particularly limited. The four inclined portions 41a, 41b, 42a, and 42b may be provided at any position and range. For example, as shown in FIG. 6A, the non-inclined region between the first inclined part 41a and the second inclined part 41b, and the third inclined part 42a and the fourth inclined part 42b. You may make it widen the range of the area | region which is not inclined between. Further, as shown in FIG. 6B, the first inclined portion 41a and the second inclined portion 41b are brought close to each other, and the third inclined portion 42a and the fourth inclined portion 42b are brought close to each other to be inclined. You may make it provide the 1st-4th inclination part 41a, 41b, 42a, 42b between the areas which do not exist.

  FIGS. 7A and 7B are schematic views illustrating examples of other cross-sectional shapes in the yz plane of the furnace space 30. In the above-described example, an example in which the cross-sectional shape of the furnace space 30 in the yz plane is a substantially square shape is shown, but the cross-sectional shape of the furnace space 30 in the yz plane is not limited to this, and in the xy plane. Similar to the cross-sectional shape, an inclined portion inclined with respect to the z direction may be provided.

  For example, as shown in FIG. 5A, the first inner wall surface 41 is provided with a fifth inclined portion 41e and a sixth inclined portion 41f inclined with respect to the z direction, and the second inner wall surface 42 is provided. A seventh inclined portion 42e and an eighth inclined portion 42f that are inclined with respect to the z direction may be provided. Further, as shown in FIG. 4B, the first to fourth inclined portions 41a, 41b, 42a, 42b may be inclined not only in the x direction but also in the z direction. .

  In this case, it goes without saying that various shapes as described in FIGS. 5 and 6 can be adopted as the cross-sectional shape of the furnace space 30 in the yz plane. Moreover, the cross-sectional shape in the xy plane and the cross-sectional shape in the yz plane of the in-furnace space 30 may be made equal or different.

  FIG. 7C is a schematic view showing an example in which the heat generating surface 21 is also inclined with respect to the z direction. In this example, the heating device 20 is composed of a long burner 20a and a short burner 20b with a narrow interval, and the burners 20a and 20b are inclined with respect to the z direction, so that the heat generating surface 21 is only in the x direction. It is made to incline also with respect to z direction instead. Thus, the heat generating surface 21 may be disposed so as to be inclined with respect to the z direction.

  In this way, even when the interval between the two burners 20a and 20b is reduced, the distance from the heat generating surface 21 to the object to be heated 100 on the transfer device 110 in the width direction (z direction) of the transfer device 110 is reduced. Since it can adjust suitably, the heating amount of the to-be-heated object 100 mounted in the width direction both ends of the conveying apparatus 110 and the heating amount of the to-be-heated object 100 mounted in the center part are more highly accurate. Can be balanced.

  In this case, the heat generating surface 21 may be inclined with respect to the z direction together with the inclination of the first inner wall surface 41 and the second inner wall surface 42 on which the heating device 20 is disposed. Instead of inclining the wall surface 41 and the second inner wall surface 42 with respect to the z direction, only the heat generating surface 21 may be inclined with respect to the z direction. Further, in the example shown in FIG. 2C, one heating device 20 is constituted by the burners 20a and 20b having different lengths, but two burners 20a and 20b having the same length are arranged in the z direction. Needless to say, it may be inclined, and when the interval between the two burners 20a and 20b is increased, it may be further inclined with respect to the z direction.

  Next, the usage mode of the heating furnace 1 will be described. FIGS. 8A to 8C are schematic views illustrating examples of usage modes of the heating furnace 1. The heating furnace 1 of the present embodiment is particularly suitable when the dimension in the Z direction perpendicular to the transport direction T in the horizontal plane is longer than the transport direction T of the article to be heated 100, that is, the dimension in the x direction. Accordingly, the heating furnace 1 is particularly suitable not only when used alone, but also when a plurality of furnaces 1 are used in series along the transport direction T as shown in FIG. . As an example of such a use mode, for example, in baking rice crackers such as rice crackers, there is a step of repeating heating and cooling while conveying the dough, and the use in such a step is particularly suitable for the heating furnace 1.

  Further, as shown in FIG. 2B, the heating furnace 1 is formed by connecting a plurality of heating furnaces 1 along the transport direction T, thereby dividing the heating furnace 1 into a plurality of regions (that is, the furnace space 30). The tunnel heating furnace 2 may be configured. In the above example, the conveyance direction T is shown as the horizontal direction, but the conveyance direction T may be the vertical direction as shown in FIG. In this case, as shown in FIG. 5C, the heating furnace 1 may be installed in a state of being rotated 90 ° in the xy plane. Needless to say, even when the transport direction T is the vertical direction, the plurality of heating furnaces 1 may be arranged or connected along the transport direction T as described above. Further, the transport direction T may be an oblique direction.

  As described above, the heating furnace 1 according to the present embodiment includes the furnace inner space 30 that heats the article 100 to be heated, and the inner wall surface 40 that forms the furnace inner space 30. The first inner wall surface 41 and the second inner wall surface 42 are opposed to each other with the object to be heated 100 in the inner space 30 interposed therebetween, and the first inner wall surface 41 is upstream of the conveyance direction T of the object to be heated 100. The first inclined portion 41a on the side and the second inclined portion 41b on the downstream side in the conveying direction T, and the second inner wall surface 42 has the third inclined portion 42a on the upstream side in the conveying direction T. And has a fourth inclined portion 42b on the downstream side in the transport direction T, and the first inclined portion 41a and the second inclined portion 41b extend from the center O1 of the first inner wall surface 41 along the transport direction T. The third inclined portion 42 is formed so as to gradually approach the second inner wall surface 42 as the distance increases. And the fourth inclined portion 42b is formed so as to approach the inner wall surface 41 of gradually soon 1 farther along the conveying direction T from the center O2 of the second inner wall surface 42.

  By adopting such a configuration, it becomes possible to convectionly circulate the air (or other gas) in the furnace space 30 as appropriate, and the furnace space 30 can be increased more than before without performing complicated temperature control or the like. The temperature distribution can be made uniform and the energy efficiency (thermal efficiency) can be increased.

  Moreover, it is preferable that the 1st inclination part 41a and the 2nd inclination part 41b are formed mutually symmetrically, and the 3rd inclination part 42a and the 4th inclination part 42b are mutually formed symmetrically. By doing in this way, the air in the furnace space 30 can be smoothly and convectively circulated. Further, the first inner wall surface 41 and the second inner wall surface 42 are preferably formed symmetrically with each other. By doing so, the air in the furnace space 30 can be convected and circulated more smoothly and uniformly. be able to.

  The first inner wall surface 41 and the second inner wall surface 42 are preferably formed such that the dimension in the direction orthogonal to the transport direction T is greater than or equal to the dimension in the transport direction T. That is, the present invention is particularly suitable for a heating furnace having a relatively short dimension in the conveying direction T. Even in such a heating furnace, the temperature distribution in the furnace space 30 is made more uniform and energy efficient than ever. Can be increased.

  The heating furnace 1 further includes a heating device 20 that is disposed on the first inner wall surface 41 or the second inner wall surface 42 and heats the article 100 to be heated by the heat generating surface 21 that generates heat. In the first inner wall surface 41, upstream or downstream in the transport direction T from the center O <b> 1 of the first inner wall surface 41, or in the transport direction T from the center O <b> 2 of the second inner wall surface 42 in the second inner wall surface 42. Are disposed on the upstream side or the downstream side of the furnace, and the heat generating surface 21 is inclined so as to face the center O side of the in-furnace space 30.

  By doing in this way, there is an inflow of outside air from the carry-in port 12a and an outflow of furnace air from the carry-out port 13a due to a synergistic effect with the first to fourth inclined portions 41a, 41b, 42a, 42b. In this case, the temperature distribution in the furnace space 30 can be made uniform and the energy efficiency can be increased.

  The heating device 20 is disposed on the upstream side and the downstream side in the transport direction T on the first inner wall surface 41, and is disposed on the upstream side and the downstream side in the transport direction T on the second inner wall surface 42, respectively. ing. By doing in this way, the influence of the inflow and outflow of the air from the carrying-in port 12a and the carrying-out port 13a can be reduced more effectively.

  In addition, the heating furnace 1 is provided on the upstream side in the transport direction T, and is provided on the downstream side in the transport direction T with the carry-in port 12a that is an opening for carrying the target object 100 into the furnace space 30. And a carry-out port 13a which is an opening for carrying out 100 out of the furnace space 30. Since the present invention can reduce the influence of the inflow of outside air from the carry-in port 12a and the outflow of in-furnace air from the carry-out port 13a, the carry-in port 12a and the carry-out port 13a are always open in this way. In this case, it is particularly suitable.

  Further, in the first inner wall surface 41, the heating device 20 includes an upstream end (x direction negative end 41 c) or a downstream end (x direction positive side) of the first inner wall 41 in the transport direction T. It is arranged closer to the center O1 of the first inner wall surface 41 than the end portion 41d), and the second inner wall surface 42 has an upstream end portion (negative in the x direction) in the transport direction T of the second inner wall surface 42. It is arranged closer to the center O2 of the second inner wall surface 42 than the side end 42c) or the downstream end (x-direction positive end 42d). By doing in this way, the influence of the inflow and outflow of the air from the carrying-in port 12a and the carrying-out port 13a can be reduced more effectively.

  Further, the heat generating surface 21 is arranged such that the longitudinal direction is orthogonal to the transport direction T and the width direction is inclined with respect to the transport direction T. The present invention is particularly suitable when the heat generating surface 21 is disposed horizontally long in the transport direction T as described above.

  A plurality of the heating devices 20 are arranged symmetrically with respect to the center O of the furnace space 30. By doing in this way, the influence of the inflow and outflow of air from the carry-in port 12a and the carry-out port 13a can be reduced more effectively, and the temperature distribution and energy efficiency of the furnace space 30 can be further improved.

  Moreover, it is preferable that inclination-angle (theta) 5 with respect to the conveyance direction T of the heat generating surface 21 is 10-30 degrees. By doing in this way, the influence of the inflow and outflow of the air from the carrying-in port 12a and the carrying-out port 13a can be reduced more effectively.

  In the present embodiment, an example in which the first to fourth inclined portions 41a, 41b, 42a, and 42b are configured from a plane is shown, but the present invention is not limited to this, and the first to fourth The inclined portions 41a, 41b, 42a, 42b may be formed of curved surfaces. Moreover, you may make it comprise the other part of the inner wall surface 40 from a curved surface.

  In the present embodiment, the first inclined portion 41a and the second inclined portion 41b are formed symmetrically with each other, and the third inclined portion 42a and the fourth inclined portion 42b are formed symmetrically with each other. However, depending on the configuration of the heating device 20 and the heating mode of the article to be heated 100, the first inclined portion 41a and the second inclined portion 41b are formed asymmetric with each other, or the third inclined portion 42a and the fourth inclined portion are formed. You may make it form the part 42b asymmetrically.

  Moreover, in this embodiment, although the example which formed the 1st inner wall surface 41 and the 2nd inner wall surface 42 symmetrically was shown, the cross-sectional shape in xy plane of the furnace space 30 is comprised in a heptagon shape, for example. For example, the first inner wall surface 41 and the second inner wall surface 42 may be formed asymmetric with respect to each other.

  Moreover, although the example provided with the four heating apparatuses 20 was shown in this embodiment, the number of the heating apparatuses 20 may be other than this. Moreover, when providing the some heating apparatus 20, you may make it include the thing which does not incline the heat generating surface 21 with respect to the conveyance direction T. FIG.

  Moreover, in this embodiment, although the example which has arrange | positioned the some heating apparatus 20 symmetrically with respect to the center O of the furnace space 30 was shown, depending on the structure of the heating apparatus 20, the heating aspect of the to-be-heated object 100, etc., You may make it arrange | position asymmetrically. For example, the heating device 20 may be disposed only on the first inner wall surface 41 or only on the second inner wall surface 42. Further, for example, the heating device 20 may be arranged only on the upstream side in the transport direction T of the first inner wall surface 41 and on the downstream side in the transport direction T of the second inner wall surface 42.

  Moreover, in this embodiment, although the example which has arrange | positioned the heating apparatus 20 to the 1st-4th inclination part 41a, 41b, 42a, 42b was shown, the 1st inner wall surface 41 or the 2nd inner wall surface 42 in the 1st. You may make it arrange | position the heating apparatus 20 in parts other than the 1st-4th inclination part 41a, 41b, 42a, 42b. Further, an additional heating device may be disposed in a portion other than the first inner wall surface 41 and the second inner wall surface 42.

  In the present embodiment, an example of a continuous heating furnace is shown, but the present invention may be applied to a batch-type heating furnace that heats a stationary object 100 to be heated. Moreover, you may make it provide a door in the carry-in entrance 12a and the carry-out exit 13a.

  As mentioned above, although embodiment of this invention was described, the heating furnace of this invention is not limited to above-described embodiment, In the range which does not deviate from the summary of this invention, it can add various changes. Of course.

  Next, examples of the present invention will be described.

  In the present example, the heating furnace 1 of the above embodiment was actually manufactured, and a heating test was performed to measure the temperature distribution in the furnace space 30 and the fuel consumption. As a comparative example, the same heating test was performed on the conventional heating furnace 200 used in the baking process of rice crackers such as rice crackers, and the test results were compared.

  FIGS. 9A and 9B are schematic views showing a conventional heating furnace 200 of a comparative example, and FIGS. 10A and 10B are schematic views showing the heating furnace 1 of the present embodiment. It is. 9 (a) and 10 (a) are schematic cross-sectional views (cross-sectional views in the zx plane) seen from above, and FIGS. 9 (b) and 10 (b) are schematic views seen from the front. It is sectional drawing (sectional drawing in xy plane).

  The comparative heating furnace 200 is used to bake rice cracker dough. As shown in FIGS. 9A and 9B, the heating furnace 200 includes a left furnace wall 212, a right furnace wall 213, a front furnace wall 214, and a rear furnace wall 215 that are vertically provided. These furnace walls 212 to 215 have a structure including a heat insulating material. Three heating devices 220 are disposed at the upper and lower portions of the furnace space 230 of the heating furnace 200, respectively, and a metal block plate is provided between the heating devices 220. The space 30 is formed in a substantially rectangular parallelepiped shape.

  Each heating device 220 is composed of an infrared burner, and the heat generating surface 221 that generates heat is directed substantially vertically downward in the heating device 220 disposed in the upper portion, and directed substantially vertically upward in the heating device 220 disposed in the lower portion. It has been. The rice confectionery dough, which is the object to be heated, is conveyed by a wire mesh endless belt with the conveying direction T as the positive x direction, and the furnace interior space 230 is provided from a carry-in port 212a provided in the left furnace wall 212. It is carried in and carried out from a carry-out port 213a provided in the right furnace wall 213.

  The heating furnace 1 of this example was manufactured with the dimensions shown in FIGS. 10A and 10B so as to have the same dimensions as the heating furnace 200 of the comparative example. In addition, the inclination angles θ1 to θ4 of the first to fourth inclined portions 41a, 41b, 42a, and 42b and the inclination angle θ5 of the heat generating surface 21 were each 20 ° as shown in the above embodiment. The number (four) of the heating devices 20 included in the heating furnace 1 is smaller than the number (six) of the heating devices 220 included in the heating furnace 200, and the total area of the heat generating surface 21 is the total area of the heat generating surface 221. Is smaller than

  In the heating test, the flow rate of the fuel gas, the pressure of the fuel gas, and the temperature of the furnace spaces 30 and 230 were measured. The temperature of the furnace spaces 30 and 230 was measured by arranging a wire mesh equivalent to the endless belt of the transport device according to the transport height of the object to be heated, and installing temperature sensors on the top and bottom surfaces of the wire mesh. As shown in FIGS. 9 and 10, nine points A to I were set as temperature measurement points according to the passing position of the heated object to be conveyed. That is, temperature measurement was performed at a total of 18 points on the upper and lower surfaces of the wire mesh at points A to I.

  FIG. 11 is a table showing the results of the heating test. In the heating test, heating is performed for 1 hour so as to maintain the temperature of the central portion (measurement point E) of the furnace spaces 30 and 230 at about 250 ° C., and in this case, the fuel gas pressure required is measured, The fuel gas flow rate and the temperature of the upper and lower surfaces at points A to I were measured every 30 minutes.

  As shown in the figure, when the central portions of the furnace spaces 30 and 230 are maintained at about 250 ° C., the fuel gas pressure and the fuel gas flow rate required in the heating furnace 1 are both required in the heating furnace 200. The fuel gas pressure and the fuel gas flow rate are lower. In particular, the fuel gas flow rate required in the heating furnace 1 is about 70% of the fuel gas flow rate required in the heating furnace 200, and the heating furnace 1 has higher energy efficiency than the heating furnace 200. confirmed.

  Further, when the temperatures of the points A to I are compared, in the heating furnace 200, a plurality of measurement points having a temperature of 200 ° C. or less are seen, whereas in the heating furnace 1, almost all of the points A to I are all. The temperature can be maintained at 230 ° C. or higher. In particular, in the heating furnace 1, it is possible to keep the temperatures at points A, C, G, and I, which tend to be low in the heating furnace 200, and the temperature distribution in the furnace space 30 can be changed. It was confirmed that it could be maintained in a more uniform state than 200.

  The heating furnace of the present invention is not limited to the field of manufacturing foods such as rice crackers and baked confectionery, but also manufactures various products that require heating, such as ceramic products such as tiles, tiles, and ceramics, glass products, and metal products. It can be used in the field of

DESCRIPTION OF SYMBOLS 1 Heating furnace 12a Carry-in port 13a Carry-out port 20 Heating device 21 Heat generating surface 30 Furnace space 40 Inner wall surface 41 First inner wall surface 41a First inclined portion 41b Second inclined portion 41c Negative x direction of first inner wall surface Side end portion 41d x-direction positive side end portion of first inner wall surface 42 second inner wall surface 42a third inclined portion 42b fourth inclined portion 42c x-direction negative side end portion 42d of second inner wall surface 42d second 100 x Heated object O Center of furnace inner space O1 Center of first inner wall surface O2 Center of second inner wall surface T Transport direction of object to be heated θ5 Inclination angle of heating surface

Claims (4)

A furnace space for heating an object to be heated;
An inner wall surface having a first inner wall surface and a second inner wall surface facing each other across an object to be heated in the furnace space, and forming the furnace space;
A heating device that is disposed on the first inner wall surface and the second inner wall surface and heats the object to be heated by a heat generating surface that generates heat, and
The first inner wall surface has a first inclined portion on the upstream side in the transport direction of the object to be heated and a second inclined portion on the downstream side in the transport direction,
The second inner wall surface has a third inclined portion on the upstream side in the transport direction and a fourth inclined portion on the downstream side in the transport direction,
The first inclined portion and the second inclined portion are formed so as to gradually approach the second inner wall surface as they move away from the center of the first inner wall surface along the transport direction,
The third inclined portion and the fourth inclined portion are formed so as to gradually approach the first inner wall surface as moving away from the center of the second inner wall surface along the transport direction,
The heating device has an upstream side and a downstream side in the transport direction from the center of the first inner wall surface of the first inner wall surface, and a center of the second inner wall surface of the second inner wall surface. In addition to being arranged on the upstream side and the downstream side in the transport direction, the heating surface is inclined and arranged so as to face the center side of the space in the furnace,
heating furnace. The heating device is
In the first inner wall surface, the first inner wall surface is disposed closer to the center of the first inner wall surface than the upstream end portion and the downstream end portion in the transport direction,
The second inner wall surface is disposed closer to the center of the second inner wall surface than the upstream end portion and the downstream end portion in the transport direction of the second inner wall surface. To
The heating furnace according to claim 1. A carry-in entrance which is provided on the upstream side in the carrying direction and is an opening for carrying the heated object into the furnace space;
A discharge port which is provided on the downstream side in the transfer direction and is an opening for discharging the object to be heated from the space in the furnace.
The heating furnace according to claim 1 or 2. The inclination angle of the heat generating surface with respect to the transport direction is 10 to 30 °,
The heating furnace according to any one of claims 1 to 3.